Whenever new
Spark Plugs are installed, the spark plug wires should be inspected, starting with a visual inspection that can be performed at the dealer or in a dark garage with good ventilation while the engine is running. Examine each plug wire for arcing or little sparks at the site of damage. If damage is found, new wires will be needed. After the engine cools, the distributor cap and rotor should be checked. Make sure to check each spark plug wire independently to ensure they remain in the correct order. Use a numbered label or tape if necessary. To disconnect the wire from the spark plug, simply twist the rubber boot and pull it free. Do not pull on the wire itself. Ensure there is no corrosion in the boot and fit tightly when fixing it back. Wipe the wire with a rag and examine it for burn marks or cracks. Do not comfortably bend the wire. Remove the wire at the distributor and observe for corrosion and fit before replace. After checking all wires, if replacement is necessary, then purchase a set specific to your engine model. Replace one wire at a time to maintain firing order. To check for cracks or worn contacts, you must remove the distributor cap. Take off the rotor and check it too, replacing any damaged parts. It's best to put a new cap and rotor on with new spark plug wires. If you're re-using the old cap, however, you should clean the terminals. Make sure to move the wires to the new cap one at a time to avoid getting them mixed up.